Port #[non_exhaustive] to the new attribute parsing infrastructure

JonathanBrouwer · JonathanBrouwer · commit 7558b4b9159f · 2025-07-02T08:55:04.000+02:00
Signed-off-by: Jonathan Brouwer &lt;jonathantbrouwer@gmail.com&gt;
diff --git a/compiler/rustc_attr_data_structures/src/attributes.rs b/compiler/rustc_attr_data_structures/src/attributes.rs
@@ -281,6 +281,9 @@ pub enum AttributeKind {
     /// Represents `#[no_mangle]`
     NoMangle(Span),
 
+    /// Represents `#[non_exhaustive]`
+    NonExhaustive(Span),
+
     /// Represents `#[optimize(size|speed)]`
     Optimize(OptimizeAttr, Span),
 
diff --git a/compiler/rustc_attr_data_structures/src/encode_cross_crate.rs b/compiler/rustc_attr_data_structures/src/encode_cross_crate.rs
@@ -26,6 +26,7 @@ impl AttributeKind {
             Inline(..) => No,
             LinkSection { .. } => No,
             MacroTransparency(..) => Yes,
+            NonExhaustive(..) => Yes,
             Repr(..) => No,
             Stability { .. } => Yes,
             Cold(..) => No,
diff --git a/compiler/rustc_attr_parsing/src/attributes/mod.rs b/compiler/rustc_attr_parsing/src/attributes/mod.rs
@@ -35,6 +35,7 @@ pub(crate) mod link_attrs;
 pub(crate) mod lint_helpers;
 pub(crate) mod loop_match;
 pub(crate) mod must_use;
+pub(crate) mod non_exhaustive;
 pub(crate) mod repr;
 pub(crate) mod rustc_internal;
 pub(crate) mod semantics;
diff --git a/compiler/rustc_attr_parsing/src/attributes/non_exhaustive.rs b/compiler/rustc_attr_parsing/src/attributes/non_exhaustive.rs
@@ -0,0 +1,25 @@
+use rustc_attr_data_structures::AttributeKind;
+use rustc_feature::{AttributeTemplate, template};
+use rustc_span::{Symbol, sym};
+
+use crate::attributes::{AttributeOrder, OnDuplicate, SingleAttributeParser};
+use crate::context::{AcceptContext, Stage};
+use crate::parser::ArgParser;
+
+pub(crate) struct NonExhaustiveParser;
+
+impl<S: Stage> SingleAttributeParser<S> for NonExhaustiveParser {
+    const PATH: &[Symbol] = &[sym::non_exhaustive];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepLast;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+
+    const TEMPLATE: AttributeTemplate = template!(Word);
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        if let Err(span) = args.no_args() {
+            cx.expected_no_args(span);
+            return None;
+        }
+        Some(AttributeKind::NonExhaustive(cx.attr_span))
+    }
+}
diff --git a/compiler/rustc_attr_parsing/src/context.rs b/compiler/rustc_attr_parsing/src/context.rs
@@ -26,6 +26,7 @@ use crate::attributes::link_attrs::{LinkNameParser, LinkSectionParser};
 use crate::attributes::lint_helpers::{AsPtrParser, PubTransparentParser};
 use crate::attributes::loop_match::{ConstContinueParser, LoopMatchParser};
 use crate::attributes::must_use::MustUseParser;
+use crate::attributes::non_exhaustive::NonExhaustiveParser;
 use crate::attributes::repr::{AlignParser, ReprParser};
 use crate::attributes::rustc_internal::{
     RustcLayoutScalarValidRangeEnd, RustcLayoutScalarValidRangeStart,
@@ -132,6 +133,7 @@ attribute_parsers!(
         Single<MayDangleParser>,
         Single<MustUseParser>,
         Single<NoMangleParser>,
+        Single<NonExhaustiveParser>,
         Single<OptimizeParser>,
         Single<PubTransparentParser>,
         Single<RustcForceInlineParser>,
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
@@ -778,9 +778,11 @@ fn lower_variant<'tcx>(
         fields,
         parent_did.to_def_id(),
         recovered,
-        adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive)
-            || variant_did
-                .is_some_and(|variant_did| tcx.has_attr(variant_did, sym::non_exhaustive)),
+        adt_kind == AdtKind::Struct
+            && find_attr!(tcx.get_all_attrs(parent_did), AttributeKind::NonExhaustive(..))
+            || variant_did.is_some_and(|variant_did| {
+                find_attr!(tcx.get_all_attrs(variant_did), AttributeKind::NonExhaustive(..))
+            }),
     )
 }
 
diff --git a/compiler/rustc_middle/src/ty/adt.rs b/compiler/rustc_middle/src/ty/adt.rs
@@ -4,6 +4,7 @@ use std::ops::Range;
 use std::str;
 
 use rustc_abi::{FIRST_VARIANT, ReprOptions, VariantIdx};
+use rustc_attr_data_structures::{AttributeKind, find_attr};
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::intern::Interned;
@@ -278,7 +279,9 @@ impl AdtDefData {
         debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
         let mut flags = AdtFlags::NO_ADT_FLAGS;
 
-        if kind == AdtKind::Enum && tcx.has_attr(did, sym::non_exhaustive) {
+        if kind == AdtKind::Enum
+            && find_attr!(tcx.get_all_attrs(did), AttributeKind::NonExhaustive(..))
+        {
             debug!("found non-exhaustive variant list for {:?}", did);
             flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
         }
diff --git a/compiler/rustc_parse/src/validate_attr.rs b/compiler/rustc_parse/src/validate_attr.rs
@@ -300,6 +300,7 @@ fn emit_malformed_attribute(
             | sym::cold
             | sym::naked
             | sym::no_mangle
+            | sym::non_exhaustive
             | sym::must_use
             | sym::track_caller
             | sym::link_name
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
@@ -188,6 +188,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 Attribute::Parsed(AttributeKind::TrackCaller(attr_span)) => {
                     self.check_track_caller(hir_id, *attr_span, attrs, span, target)
                 }
+                Attribute::Parsed(AttributeKind::NonExhaustive(attr_span)) => {
+                    self.check_non_exhaustive(hir_id, *attr_span, span, target, item)
+                }
                 Attribute::Parsed(
                     AttributeKind::RustcLayoutScalarValidRangeStart(_num, attr_span)
                     | AttributeKind::RustcLayoutScalarValidRangeEnd(_num, attr_span),
@@ -228,7 +231,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         [sym::no_sanitize, ..] => {
                             self.check_no_sanitize(attr, span, target)
                         }
-                        [sym::non_exhaustive, ..] => self.check_non_exhaustive(hir_id, attr, span, target, item),
                         [sym::marker, ..] => self.check_marker(hir_id, attr, span, target),
                         [sym::target_feature, ..] => {
                             self.check_target_feature(hir_id, attr, span, target, attrs)
@@ -755,7 +757,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     fn check_non_exhaustive(
         &self,
         hir_id: HirId,
-        attr: &Attribute,
+        attr_span: Span,
         span: Span,
         target: Target,
         item: Option<ItemLike<'_>>,
@@ -770,7 +772,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     && fields.iter().any(|f| f.default.is_some())
                 {
                     self.dcx().emit_err(errors::NonExhaustiveWithDefaultFieldValues {
-                        attr_span: attr.span(),
+                        attr_span,
                         defn_span: span,
                     });
                 }
@@ -781,13 +783,11 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             // erroneously allowed it and some crates used it accidentally, to be compatible
             // with crates depending on them, we can't throw an error here.
             Target::Field | Target::Arm | Target::MacroDef => {
-                self.inline_attr_str_error_with_macro_def(hir_id, attr.span(), "non_exhaustive");
+                self.inline_attr_str_error_with_macro_def(hir_id, attr_span, "non_exhaustive");
             }
             _ => {
-                self.dcx().emit_err(errors::NonExhaustiveWrongLocation {
-                    attr_span: attr.span(),
-                    defn_span: span,
-                });
+                self.dcx()
+                    .emit_err(errors::NonExhaustiveWrongLocation { attr_span, defn_span: span });
             }
         }
     }
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
@@ -5,7 +5,7 @@ use rustc_ast::{
     self as ast, CRATE_NODE_ID, Crate, ItemKind, MetaItemInner, MetaItemKind, ModKind, NodeId, Path,
 };
 use rustc_ast_pretty::pprust;
-use rustc_attr_data_structures::{self as attr, Stability};
+use rustc_attr_data_structures::{self as attr, AttributeKind, Stability, find_attr};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
@@ -1998,9 +1998,9 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // Otherwise, point out if the struct has any private fields.
         if let Some(def_id) = res.opt_def_id()
             && !def_id.is_local()
-            && let Some(attr) = self.tcx.get_attr(def_id, sym::non_exhaustive)
+            && let Some(attr_span) = find_attr!(self.tcx.get_all_attrs(def_id), AttributeKind::NonExhaustive(span) => *span)
         {
-            non_exhaustive = Some(attr.span());
+            non_exhaustive = Some(attr_span);
         } else if let Some(span) = ctor_fields_span {
             let label = errors::ConstructorPrivateIfAnyFieldPrivate { span };
             err.subdiagnostic(label);
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
@@ -7,7 +7,7 @@ use arrayvec::ArrayVec;
 use itertools::Either;
 use rustc_abi::{ExternAbi, VariantIdx};
 use rustc_attr_data_structures::{
-    AttributeKind, ConstStability, Deprecation, Stability, StableSince,
+    AttributeKind, ConstStability, Deprecation, Stability, StableSince, find_attr,
 };
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_hir::def::{CtorKind, DefKind, Res};
@@ -621,7 +621,7 @@ impl Item {
     }
 
     pub(crate) fn is_non_exhaustive(&self) -> bool {
-        self.attrs.other_attrs.iter().any(|a| a.has_name(sym::non_exhaustive))
+        find_attr!(&self.attrs.other_attrs, AttributeKind::NonExhaustive(..))
     }
 
     /// Returns a documentation-level item type from the item.
@@ -763,6 +763,8 @@ impl Item {
                 } else if let hir::Attribute::Parsed(AttributeKind::ExportName { name, .. }) = attr
                 {
                     Some(format!("#[export_name = \"{name}\"]"))
+                } else if let hir::Attribute::Parsed(AttributeKind::NonExhaustive(..)) = attr {
+                    Some("#[non_exhaustive]".to_string())
                 } else if is_json {
                     match attr {
                         // rustdoc-json stores this in `Item::deprecation`, so we
diff --git a/src/tools/clippy/clippy_lints/src/exhaustive_items.rs b/src/tools/clippy/clippy_lints/src/exhaustive_items.rs
@@ -4,7 +4,9 @@ use rustc_errors::Applicability;
 use rustc_hir::{Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::declare_lint_pass;
-use rustc_span::sym;
+use rustc_attr_data_structures::AttributeKind;
+use rustc_attr_data_structures::find_attr;
+
 
 declare_clippy_lint! {
     /// ### What it does
@@ -85,7 +87,7 @@ impl LateLintPass<'_> for ExhaustiveItems {
         };
         if cx.effective_visibilities.is_exported(item.owner_id.def_id)
             && let attrs = cx.tcx.hir_attrs(item.hir_id())
-            && !attrs.iter().any(|a| a.has_name(sym::non_exhaustive))
+            && !find_attr!(attrs, AttributeKind::NonExhaustive(..))
             && fields.iter().all(|f| cx.tcx.visibility(f.def_id).is_public())
         {
             span_lint_and_then(cx, lint, item.span, msg, |diag| {
diff --git a/src/tools/clippy/clippy_lints/src/manual_non_exhaustive.rs b/src/tools/clippy/clippy_lints/src/manual_non_exhaustive.rs
@@ -4,15 +4,16 @@ use clippy_utils::is_doc_hidden;
 use clippy_utils::msrvs::{self, Msrv};
 use clippy_utils::source::snippet_indent;
 use itertools::Itertools;
-use rustc_ast::attr;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
 use rustc_hir::{Expr, ExprKind, Item, ItemKind, QPath, TyKind, VariantData};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::impl_lint_pass;
 use rustc_span::def_id::LocalDefId;
-use rustc_span::{Span, sym};
+use rustc_span::Span;
+use rustc_attr_data_structures::find_attr;
+use rustc_attr_data_structures::AttributeKind;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -93,7 +94,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualNonExhaustive {
                         .then_some((v.def_id, v.span))
                 });
                 if let Ok((id, span)) = iter.exactly_one()
-                    && !attr::contains_name(cx.tcx.hir_attrs(item.hir_id()), sym::non_exhaustive)
+                    && !find_attr!(cx.tcx.hir_attrs(item.hir_id()), AttributeKind::NonExhaustive(..))
                 {
                     self.potential_enums.push((item.owner_id.def_id, id, item.span, span));
                 }
@@ -113,10 +114,10 @@ impl<'tcx> LateLintPass<'tcx> for ManualNonExhaustive {
                         item.span,
                         "this seems like a manual implementation of the non-exhaustive pattern",
                         |diag| {
-                            if let Some(non_exhaustive) =
-                                attr::find_by_name(cx.tcx.hir_attrs(item.hir_id()), sym::non_exhaustive)
+                            if let Some(non_exhaustive_span) =
+                                find_attr!(cx.tcx.hir_attrs(item.hir_id()), AttributeKind::NonExhaustive(span) => *span)
                             {
-                                diag.span_note(non_exhaustive.span(), "the struct is already non-exhaustive");
+                                diag.span_note(non_exhaustive_span, "the struct is already non-exhaustive");
                             } else {
                                 let indent = snippet_indent(cx, item.span).unwrap_or_default();
                                 diag.span_suggestion_verbose(
diff --git a/src/tools/clippy/clippy_utils/src/attrs.rs b/src/tools/clippy/clippy_utils/src/attrs.rs
@@ -7,9 +7,10 @@ use rustc_middle::ty::{AdtDef, TyCtxt};
 use rustc_session::Session;
 use rustc_span::{Span, Symbol};
 use std::str::FromStr;
-
+use rustc_attr_data_structures::find_attr;
 use crate::source::SpanRangeExt;
 use crate::{sym, tokenize_with_text};
+use rustc_attr_data_structures::AttributeKind;
 
 /// Deprecation status of attributes known by Clippy.
 pub enum DeprecationStatus {
@@ -165,13 +166,13 @@ pub fn is_doc_hidden(attrs: &[impl AttributeExt]) -> bool {
 
 pub fn has_non_exhaustive_attr(tcx: TyCtxt<'_>, adt: AdtDef<'_>) -> bool {
     adt.is_variant_list_non_exhaustive()
-        || tcx.has_attr(adt.did(), sym::non_exhaustive)
+        || find_attr!(tcx.get_all_attrs(adt.did()), AttributeKind::NonExhaustive(..))
         || adt.variants().iter().any(|variant_def| {
-            variant_def.is_field_list_non_exhaustive() || tcx.has_attr(variant_def.def_id, sym::non_exhaustive)
+            variant_def.is_field_list_non_exhaustive() || find_attr!(tcx.get_all_attrs(variant_def.def_id), AttributeKind::NonExhaustive(..))
         })
         || adt
             .all_fields()
-            .any(|field_def| tcx.has_attr(field_def.did, sym::non_exhaustive))
+            .any(|field_def| find_attr!(tcx.get_all_attrs(field_def.did), AttributeKind::NonExhaustive(..)))
 }
 
 /// Checks if the given span contains a `#[cfg(..)]` attribute
diff --git a/tests/ui/attributes/malformed-attrs.stderr b/tests/ui/attributes/malformed-attrs.stderr
@@ -218,12 +218,6 @@ error: malformed `automatically_derived` attribute input
 LL | #[automatically_derived = 18]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[automatically_derived]`
 
-error: malformed `non_exhaustive` attribute input
-  --> $DIR/malformed-attrs.rs:195:1
-   |
-LL | #[non_exhaustive = 1]
-   | ^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[non_exhaustive]`
-
 error: malformed `thread_local` attribute input
   --> $DIR/malformed-attrs.rs:201:1
    |
@@ -546,6 +540,15 @@ LL | #[rustc_layout_scalar_valid_range_end]
    | expected this to be a list
    | help: must be of the form: `#[rustc_layout_scalar_valid_range_end(end)]`
 
+error[E0565]: malformed `non_exhaustive` attribute input
+  --> $DIR/malformed-attrs.rs:195:1
+   |
+LL | #[non_exhaustive = 1]
+   | ^^^^^^^^^^^^^^^^^---^
+   | |                |
+   | |                didn't expect any arguments here
+   | help: must be of the form: `#[non_exhaustive]`
+
 warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
   --> $DIR/malformed-attrs.rs:147:1
    |
diff --git a/tests/ui/lint/unused/unused-attr-duplicate.stderr b/tests/ui/lint/unused/unused-attr-duplicate.stderr
@@ -65,18 +65,6 @@ LL | #[should_panic]
    | ^^^^^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
-error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:66:1
-   |
-LL | #[non_exhaustive]
-   | ^^^^^^^^^^^^^^^^^ help: remove this attribute
-   |
-note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:65:1
-   |
-LL | #[non_exhaustive]
-   | ^^^^^^^^^^^^^^^^^
-
 error: unused attribute
   --> $DIR/unused-attr-duplicate.rs:70:1
    |
@@ -202,6 +190,18 @@ LL | #[must_use]
    | ^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
+error: unused attribute
+  --> $DIR/unused-attr-duplicate.rs:66:1
+   |
+LL | #[non_exhaustive]
+   | ^^^^^^^^^^^^^^^^^ help: remove this attribute
+   |
+note: attribute also specified here
+  --> $DIR/unused-attr-duplicate.rs:65:1
+   |
+LL | #[non_exhaustive]
+   | ^^^^^^^^^^^^^^^^^
+
 error: unused attribute
   --> $DIR/unused-attr-duplicate.rs:74:1
    |
diff --git a/tests/ui/rfcs/rfc-2008-non-exhaustive/invalid-attribute.stderr b/tests/ui/rfcs/rfc-2008-non-exhaustive/invalid-attribute.stderr
@@ -1,8 +1,11 @@
-error: malformed `non_exhaustive` attribute input
+error[E0565]: malformed `non_exhaustive` attribute input
   --> $DIR/invalid-attribute.rs:1:1
    |
 LL | #[non_exhaustive(anything)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[non_exhaustive]`
+   | ^^^^^^^^^^^^^^^^----------^
+   | |               |
+   | |               didn't expect any arguments here
+   | help: must be of the form: `#[non_exhaustive]`
 
 error[E0701]: attribute should be applied to a struct or enum
   --> $DIR/invalid-attribute.rs:5:1
@@ -27,4 +30,5 @@ LL | | }
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0701`.
+Some errors have detailed explanations: E0565, E0701.
+For more information about an error, try `rustc --explain E0565`.

Original file line number	Diff line number	Diff line change
`@@ -778,9 +778,11 @@ fn lower_variant<'tcx>(`
`778`	`778`	`fields,`
`779`	`779`	`parent_did.to_def_id(),`
`780`	`780`	`recovered,`
`781`		`- adt_kind == AdtKind::Struct && tcx.has_attr(parent_did, sym::non_exhaustive)`
`782`		`- \|\| variant_did`
`783`		`- .is_some_and(\|variant_did\| tcx.has_attr(variant_did, sym::non_exhaustive)),`
	`781`	`+ adt_kind == AdtKind::Struct`
	`782`	`+ && find_attr!(tcx.get_all_attrs(parent_did), AttributeKind::NonExhaustive(..))`
	`783`	`+ \|\| variant_did.is_some_and(\|variant_did\| {`
	`784`	`+ find_attr!(tcx.get_all_attrs(variant_did), AttributeKind::NonExhaustive(..))`
	`785`	`+ }),`
`784`	`786`	`)`
`785`	`787`	`}`
`786`	`788`